A Comprehensive Simulation Scheme for Tape Casting: From Flow Behavior to Anisotropy Development

Abstract

A new simulation scheme for tape casting is presented and applied. The model allows considering both the macroscopic flow behavior and the orientation of individual particles inside the ceramic slurry. It is based on the smoothed particle hydrodynamics method, a particle‐based computational fluid dynamics solver, and Jeffery's equations of particle motion, which describe the rotation of rigid, ellipsoidal particles in a fluid. It is shown how different process parameters and the rheological behavior of the slurry influence its flow behavior, which in turn affects the orientation of nonspherical particles inside the slurry. The simulations predict that a preferred, anisotropic particle orientation develops in the green tapes, whose extent depends mainly on the powder properties. All simulations are performed with real tape‐casting data concerning geometry of casting unit, casting parameters, slurry rheology, and powder properties. The anisotropy results are confirmed by experimental analysis of cross sections of tape‐cast films made from different powders.

The effect of tape casting operational parameters on the quality of adjacently graded ceramic film

“…At the end of the process, as expected, the tape thickness cast by DB mode was equal to the thicknesses of tapes, cast with the SB and SC methods. Further optimisation on the adjustment of the gaps in the double blade set-up was discontinued due to the presence of a vortex flow in the relief reservoir, proven both experimentally [18] and numerically [19]. The vortex flow affecting the rheological behaviour of the slurry makes a shearing flow during casting uncontrollable.…”

“…The use of the SC program was also eliminated for further SBS TC test, as the shear rate profile, determining the quality of the interface [11], was proven to be dependent on the casting speed [20]. For the same reasons of high possibility of unstable flow [19] during co-casting, the work with a DB set-up was discontinued. Considering the detailed study of the multiple materials co-flow in a lab-scale tape casting, the SB approach was decided to be applied for further SBS TC tests.…”

“…Better results might be achieved if the casting gaps below both blades were adjusted. This work has been discontinued because of the presence of the vortex when high viscous slurries are applied [19]. Single blade was chosen for SBS TC process in the small lab-scale as it shows relatively small thickness gradient of below 10% after the cast first 10 mm.…”

Thickness control and interface quality as functions of slurry formulation and casting speed in side-by-side tape casting

“…Although the use of a double-blade in tape caster design was invented to keep the slurry level in pre-sheared zone constant and thus produce a smooth tape, the inhomogeneous flow inside the spare pool of tape caster 11 and complicated design of the partition needed for double blade system did not guarantee a high reproducibility of casting experiments. This favours the use of single-blade over the double-blade system for SBS TC.…”

Multiphysics modelling of manufacturing processes: A review

“…35 lead to optimizing the process by simulating more advanced features related to flow analysis. 26,[37][38][39][40][41][42] For fluid flow analysis in tape casting normally the coupled momentum and continuity equations should be solved, that is r ∂u ∂t + u Á ru = À rp + r Á T + F ð1Þ…”